Viscosupplementation is a procedure where a hyaluronic acid-based product is injected into an arthritic joint to improve pain, swelling and stiffness associated with arthritis.
Inside a healthy joint, there is a small amount of lubricating fluid called synovial fluid. The primary composition of synovial fluid is hyaluronic acid. Hyaluronic acid provides lubrication in the joint movements. It also absorbs shock which goes through the joint when it is loaded (e.g., when a person hops or jumps).
In osteoarthritis (OA), the cartilage in the joint wears out and the synovial fluid also becomes diseased and loses its lubricating and shock-absorbing abilities. The joint loses its protective mechanism and pain, stiffness and loss of function occur in the joint.
Hyaluronans are substances similar to hyaluronic acid in synovial fluid, in terms of lubricating and shock-absorbing abilities. Hyaluronans are injected into the joint affected by OA and they replace the diseased synovial fluid, protecting the already damaged cartilage lining from further damage caused by friction.
Viscosupplementation is not regarded as a first-line treatment for joint OA. Therefore, it is usually considered when conventional and evidence-based treatments, such as exercise, weight loss and physical therapy have been tried but have not resulted in the desired outcomes.
The doctor will clean the joint with antiseptic solutions. He or she may inject a local anaesthetic to the joint and withdraw some of the diseased synovial fluid from the joint before injecting the hyaluronan preparation into it. Occasionally the procedure will be guided with the use of ultrasound.
The onset of pain relief varies among individuals. Most patients experience pain relief six weeks post-injection, but there are patients who experience pain relief as soon as one week post-injection.
Viscosupplementation is not a cure for OA, and hence there may not be permanent symptom relief. A single viscosupplementation injection can provide up to an average of six months of pain relief. Hence, some patients may opt for repeat injections.
Viscosupplementation is a safe procedure. There may be pain or bleeding to the injection site. Some patients might also develop a rash. These are usually mild and do not last more than 3-5 days.
There is also a small risk of joint fluid build-up, infection, or acute swelling (flare reaction). If you have symptoms such as a fever, or find that movement is painful or the joint feels warm, see your family doctor immediately, or go to the Accident and Emergency (A&E) Department if you suspect that you have developed a joint infection or flare reaction.